What's the best way to extend joists? Removal of load bearer...

[MaccaTVR]

Hi,

I'll try keep it short and sweet but if anyone needs more info, I'm happy to give it.

Basically I'm going to be removing a section of load bearing wall and I'm wondering what would be the best way to support / extend the joists to the next load bearer (which is only around 14 inches away)

Please see my sketches...

Orange - existing joists
Green - main load bearing wall
Purple - load bearing chimney breast
Yellow - new supporting / sistering timbers

First sketch shows my current layout.

I've worked out that the section of chimney breast I want to remove will only require 2 joists needing supported - numbers 8 and 9. In other words if I knock down the chimney breast that I want then joists 8 and 9 will be left unsupported.

My second sketch shows what was suggested to me by 2 different engineers (but did not supply drawings / sizes etc as this would of cost a fair bit)
Basically it's using two additional timbers (same size as the existing) on each joist to extend it to reach the next load bearer. I think this is called sistering.

I understand it might be a bit silly to ask on here when two engineers have informally told me what to do, but I've also had another so called engineer and a couple of joiners tell me it wasn't even load bearing...

My questions are:

1. Does this seem reasonable?
2. If so, what would be the recommended overlap when sistering? I was told by the engineers it would need to be pretty long.
3. What would be the best way to actually join these together? I was originally thinking lots of coach bolts with those sharp dog tooth washers.

Any advice much appreciated.
Thanks

 

[^woody^]

With your idea, the new timber sections only need 100mm bearing on the existing wall. 600mm overlap of the joists being extended.

Other options
Scarf joint
Splice plates
600mm ply gussets, glued and screwed